In Xerography or an electrostatographic process, a uniform electrostatic charge is placed upon a photoreceptor surface. The charged surface is then exposed to a light image of an original to selectively dissipate the charge to form a latent electrostatic image of the original. The latent image is developed by depositing finely divided and charged particles of toner upon the photoreceptor surface. The charged toner being electrostatically attached to the latent electrostatic image areas to create a visible replica of the original. The developed image is then usually transferred from the photoreceptor surface to a final support material, such as paper, and the toner image is fixed thereto to form a permanent record corresponding to the original.
In Xerographic color copiers using a dry toner system, a photoreceptor surface is generally arranged to move in an endless path through the various processing stations of the color xerographic process. The color toner image is then transferred from the photoreceptor to a final support material, such as paper, and the surface of the photoreceptor is prepared to be used once again for the reproduction of a copy of a colored original. In this endless path, several stations, including color toner stations are traversed. These stations may involve one or several color toner dispensing units. In ink jet printers using a liquid ink(s), the ink cartridges are moved back and forth and spray the ink or inks using the nozzles on the paper directly. The present invention and embodiments are used in both dry ink systems and liquid inkjet printing systems.
For color printers, the ink module generally contains multiple colorants: Cyan-magenta-yellow-black is the most commonly used set. When the inks are manufactured within one ink cartridge, most of the time, some ink is going to run out before others, and therefore causes the waste of unused ink. The worst-case scenario would be that a full color ink cartridge is used to print black and white pages. Some printers would provide black only cartridges to mitigate this problem, sometimes come with the cost of inconvenient user operation to replace the cartridges between print jobs. Problems also occur when the CMYK colorants can be replaced individually, for example, most of the color laser printers. Toner cartridge replacement requires maintenance and downtime. Replacing all toner cartridges at the same time would increase the efficiency, but it might result in throwing away a cartridge which is still 50% full.
In today's complex color systems (including printers and copiers) several potential problems need to be addressed and controlled. For example, space and apparatus size must be minimized, including the size of color marking cartridges. Since the amount of colorant, ink or toner) is critical, maximum use of the available colorant is extremely important. A problem in color marking systems is to balance the consumption of the colorant so as to preserve the length of the life of the cartridge containing each colorant. In this same theme, reducing the system down time caused by cartridge replacement has been a reoccurring problem in color marking systems. It is not uncommon for one or more colorants to be exhausted or used before the others, which requires some type of either replacement, resupply, or some time consuming control.